1. Technical Field
The present invention relates to a spectacle progressive-power lens and a progressive-power lens design method.
2. Related Art
International Publication WO97/19382 describes a progressive-power lens used as a spectacle lens suitable for presbyopia correction or other vision correction and having a progressive-power eyeball-side surface instead of a progressive-power object-side surface in related art. This configuration allows the object-side surface to be a spherical surface having a fixed base curve, whereby the difference in magnification between the distance portion and the near portion can be reduced. In addition, variation in magnification caused by a shape factor can be suppressed. As a result, the amount of image shaking and distortion due to the difference in magnification can be reduced, whereby a progressive-power lens that provides a comfortable field of view can be provided. Further, International Publication WO97/19382 describes that a combination method allows a progressive-power surface and a toric surface for astigmatism correction to be combined as the eyeball-side surface to reduce the amounts of image shaking and distortion also in a progressive-power lens for astigmatism correction.
Although the above and other technologies have improved the performance of a progressive-power lens, some users still cannot adapt to the characteristics of a progressive-power lens, particularly the image shaking phenomenon, and further improvement is therefore desired.